27.2.3. Raster extraction

27.2.3.1. Clip raster by extent 

Clips any GDAL-supported raster file to a given extent.

This algorithm is derived from the GDAL translate utility.

Default menu: Raster ► Extraction

参数

Basic parameters

标注	名称	类型	描述
输入图层	`INPUT`	[栅格]	The input raster
Clipping extent	`EXTENT`	[范围]	Extent that should be used for the output raster. Only pixels within the specified bounding box will be included in the output. Available methods are: Calculate from layer…: uses extent of a layer loaded in the current project Calculate from layout map…: uses extent of a layout map item in the active project Calculate from bookmark…: uses extent of a saved bookmark Use map canvas extent Draw on canvas: click and drag a rectangle delimiting the area to take into account Enter the coordinates as `xmin, xmax, ymin, ymax`
Override the projection for the output file	`OVERCRS`	[boolean] Default: False	If checked, the output file is assigned the input layer CRS.
Assign a specified nodata value to output bands 可选	`NODATA`	[数字] Default: None	Defines a value that should be inserted for the nodata values in the output raster
Clipped (extent)	`OUTPUT`	[栅格] 默认: `[保存到临时文件]`	Specification of the output raster layer. One of: 保存到临时文件保存到文件…

Advanced parameters

标注

名称

类型

描述

Additional creation options

可选

OPTIONS

[string]

Default: ''

For adding one or more creation options that control the raster to be created (colors, block size, file compression...). For convenience, you can rely on predefined profiles (see GDAL driver options section).

Batch Process and Model Designer: separate multiple options with a pipe character (|).

Output data type

DATA_TYPE

[enumeration]

Default: 0

Defines the format of the output raster file.

Options:

0 --- Use Input Layer Data Type
1 --- Byte (Eight bit unsigned integer (quint8))
2 --- Int16 (Sixteen bit signed integer (qint16))
3 --- UInt16 (Sixteen bit unsigned integer (quint16))
4 --- UInt32 (Thirty two bit unsigned integer (quint32))
5 --- Int32 (Thirty two bit signed integer (qint32))
6 --- Float32 (Thirty two bit floating point (float))
7 --- Float64 (Sixty four bit floating point (double))
8 --- CInt16 (Complex Int16)
9 --- CInt32 (Complex Int32)
10 --- CFloat32 (Complex Float32)
11 --- CFloat64 (Complex Float64)

Available options depend on the GDAL version built with QGIS (see Help ► About menu)

Additional command-line parameters

可选

EXTRA

[string]

Default: None

Add extra GDAL command line options

输出

标注	名称	类型	描述
Clipped (extent)	`OUTPUT`	[栅格]	Output raster layer clipped by the given extent

Python代码

Algorithm ID: gdal:cliprasterbyextent

import processing
processing.run("algorithm_id", {parameter_dictionary})

当你在数据处理工具箱某个算法前悬停时，算法 id 将会展现。*参数字*将会提供参数的名称与数值。参考详见`数据处理_控制台`以获取如何从Python控制台中运行数据处理算法。

27.2.3.2. Clip raster by mask layer 

Clips any GDAL-supported raster by a vector mask layer.

This algorithm is derived from the GDAL warp utility.

Default menu: Raster ► Extraction

参数

Basic parameters

标注	名称	类型	描述
输入图层	`INPUT`	[栅格]	The input raster
Mask layer	`MASK`	[vector: polygon]	Vector mask for clipping the raster
Source CRS	`SOURCE_CRS`	[crs]	Set the coordinate reference to use for the input raster
Target CRS	`TARGET_CRS`	[crs]	Set the coordinate reference to use for the mask layer
Target extent `NEW in 3.24` 可选	`TARGET_EXTENT`	[范围]	Extent of the output file to be created Available methods are: Calculate from layer…: uses extent of a layer loaded in the current project Calculate from layout map…: uses extent of a layout map item in the active project Calculate from bookmark…: uses extent of a saved bookmark Use map canvas extent Draw on canvas: click and drag a rectangle delimiting the area to take into account Enter the coordinates as `xmin, xmax, ymin, ymax`
Assign a specified nodata value to output bands 可选	`NODATA`	[数字] Default: None	Defines a value that should be inserted for the nodata values in the output raster
Create an output alpha band	`ALPHA_BAND`	[boolean] Default: False	Creates an alpha band for the result. The alpha band then includes the transparency values of the pixels.
Match the extent of the clipped raster to the extent of the mask layer	`CROP_TO_CUTLINE`	[boolean] Default: True	Applies the vector layer extent to the output raster if checked.
Keep resolution of input raster	`KEEP_RESOLUTION`	[boolean] Default: False	The resolution of the output raster will not be changed
Set output file resolution	`SET_RESOLUTION`	[boolean] Default: False	Shall the output resolution (cell size) be specified
X Resolution to output bands 可选	`X_RESOLUTION`	[数字] Default: None	The width of the cells in the output raster
Y Resolution to output band 可选	`Y_RESOLUTION`	[数字] Default: None	The height of the cells in the output raster
Use multithreaded warping implementation	`MULTITHREADING`	[boolean] Default: False	Two threads will be used to process chunks of image and perform input/output operation simultaneously. Note that computation is not multithreaded itself.
Clipped (mask)	`OUTPUT`	[栅格] 默认: `[保存到临时文件]`	Specification of the output raster layer. One of: 保存到临时文件保存到文件…

Advanced parameters

标注

名称

类型

描述

Additional creation options

可选

OPTIONS

[string]

Default: ''

For adding one or more creation options that control the raster to be created (colors, block size, file compression...). For convenience, you can rely on predefined profiles (see GDAL driver options section).

Batch Process and Model Designer: separate multiple options with a pipe character (|).

Output data type

DATA_TYPE

[enumeration]

Default: 0

Defines the format of the output raster file.

Options:

0 --- Use Input Layer Data Type
1 --- Byte (Eight bit unsigned integer (quint8))
2 --- Int16 (Sixteen bit signed integer (qint16))
3 --- UInt16 (Sixteen bit unsigned integer (quint16))
4 --- UInt32 (Thirty two bit unsigned integer (quint32))
5 --- Int32 (Thirty two bit signed integer (qint32))
6 --- Float32 (Thirty two bit floating point (float))
7 --- Float64 (Sixty four bit floating point (double))
8 --- CInt16 (Complex Int16)
9 --- CInt32 (Complex Int32)
10 --- CFloat32 (Complex Float32)
11 --- CFloat64 (Complex Float64)

Available options depend on the GDAL version built with QGIS (see Help ► About menu)

Additional command-line parameters

可选

EXTRA

[string]

Default: None

Add extra GDAL command line options

输出

标注	名称	类型	描述
Clipped (mask)	`OUTPUT`	[栅格]	Output raster layer clipped by the vector layer

Python代码

Algorithm ID: gdal:cliprasterbymasklayer

import processing
processing.run("algorithm_id", {parameter_dictionary})

当你在数据处理工具箱某个算法前悬停时，算法 id 将会展现。*参数字*将会提供参数的名称与数值。参考详见`数据处理_控制台`以获取如何从Python控制台中运行数据处理算法。

27.2.3.3. Contour 

Extracts contour lines from any GDAL-supported elevation raster.

This algorithm is derived from the GDAL contour utility.

Default menu: Raster ► Extraction

参数

Basic parameters

标注	名称	类型	描述
输入图层	`INPUT`	[栅格]	Input raster
Band number	`BAND`	[raster band] Default: 1	Raster band to create the contours from
Interval between contour lines	`INTERVAL`	[数字] Default: 10.0	Defines the interval between the contour lines in the given units of the elevation raster (minimum value 0)
Attribute name (if not set, no elevation attribute is attached) 可选	`FIELD_NAME`	[string] Default: 'ELEV'	Provides a name for the attribute in which to put the elevation.
Offset from zero relative to which to interpret intervals 可选	`OFFSET`	[数字] Default: 0.0
Contours	`OUTPUT`	[vector: line] 默认: `[保存到临时文件]`	Specification of the output vector layer. One of: 保存到临时文件保存到文件…

Advanced parameters

标注	名称	类型	描述
Produce 3D vector	`CREATE_3D`	[boolean] Default: False	Forces production of 3D vectors instead of 2D. Includes elevation at every vertex.
Treat all raster values as valid	`IGNORE_NODATA`	[boolean] Default: False	Ignores any nodata values in the dataset.
Input pixel value to treat as "nodata" 可选	`NODATA`	[数字] Default: None	Defines a value that should be inserted for the nodata values in the output raster
Additional command-line parameters 可选	`EXTRA`	[string] Default: None	Add extra GDAL command line options. Refer to the corresponding GDAL utility documentation.

输出

标注	名称	类型	描述
Contours	`OUTPUT`	[vector: line]	Output vector layer with contour lines

Python代码

Algorithm ID: gdal:contour

import processing
processing.run("algorithm_id", {parameter_dictionary})

当你在数据处理工具箱某个算法前悬停时，算法 id 将会展现。*参数字*将会提供参数的名称与数值。参考详见`数据处理_控制台`以获取如何从Python控制台中运行数据处理算法。

27.2.3.4. Contour Polygons 

Extracts contour polygons from any GDAL-supported elevation raster.

This algorithm is derived from the GDAL contour utility.

参数

Basic parameters

标注	名称	类型	描述
输入图层	`INPUT`	[栅格]	Input raster
Band number	`BAND`	[raster band] Default: 1	Raster band to create the contours from
Interval between contour lines	`INTERVAL`	[数字] Default: 10.0	Defines the interval between the contour lines in the given units of the elevation raster (minimum value 0)
Offset from zero relative to which to interpret intervals 可选	`OFFSET`	[数字] Default: 0.0
Attribute name for minimum elevation of contour polygon 可选	`FIELD_NAME_MIN`	[string] Default: 'ELEV_MIN'	Provides a name for the attribute in which to put the minimum elevation of contour polygon. If not provided no minimum elevation attribute is attached.
Attribute name for maximum elevation of contour polygon 可选	`FIELD_NAME_MAX`	[string] Default: 'ELEV_MAX'	Provides a name for the attribute in which to put the maximum elevation of contour polygon. If not provided no maximum elevation attribute is attached.
Contours	`OUTPUT`	[vector: polygon] 默认: `[保存到临时文件]`	Specification of the output vector layer. One of: 保存到临时文件保存到文件…

Advanced parameters

标注	名称	类型	描述
Produce 3D vector	`CREATE_3D`	[boolean] Default: False	Forces production of 3D vectors instead of 2D. Includes elevation at every vertex.
Treat all raster values as valid	`IGNORE_NODATA`	[boolean] Default: False	Ignores any nodata values in the dataset.
Input pixel value to treat as "nodata" 可选	`NODATA`	[数字] Default: None	Defines a value that should be inserted for the nodata values in the output raster
Additional command-line parameters 可选	`EXTRA`	[string] Default: None	Add extra GDAL command line options. Refer to the corresponding GDAL utility documentation.

输出

标注	名称	类型	描述
Contours	`OUTPUT`	[vector: polygon]	Output vector layer with contour polygons

Python代码

Algorithm ID: gdal:contour_polygon

import processing
processing.run("algorithm_id", {parameter_dictionary})

当你在数据处理工具箱某个算法前悬停时，算法 id 将会展现。*参数字*将会提供参数的名称与数值。参考详见`数据处理_控制台`以获取如何从Python控制台中运行数据处理算法。

27.2.3. Raster extraction

27.2.3.1. Clip raster by extent

参数

Basic parameters

Advanced parameters

输出

Python代码

27.2.3.2. Clip raster by mask layer

参数

Basic parameters

Advanced parameters

输出

Python代码

27.2.3.3. Contour

参数

Basic parameters

Advanced parameters

输出

Python代码

27.2.3.4. Contour Polygons

参数

Basic parameters

Advanced parameters

输出

Python代码

27.2.3.1. Clip raster by extent 

27.2.3.2. Clip raster by mask layer 

27.2.3.3. Contour 

27.2.3.4. Contour Polygons 